WO2018185393A1 - Lighting device for a vehicle including a flexible oled associated with electromechanical deformation means - Google Patents

Abstract

The present invention relates to a lighting device for a motor vehicle including at least one areal light source formed by an organic light-emitting diode (11); characterized in that said organic light-emitting diode (11) is of flexible type (FOLED) and in that said device furthermore includes electromechanical means (13) able to interact with at least one portion (11B) of said FOLED (11) so as to bring about deformation thereof. The invention also targets an optical signalling unit including at least one such lighting device.

Description

 Title of the invention

 Vehicle light device having a flexible OLED associated with electromechanical deformation means

Field of the invention

 The present invention relates generally to the field of signaling light devices for motor vehicles.

Background of the invention

 Signal lights (sidelights, stop lights, direction indicators, reversing lights, rear fog lamps and daytime running lights) are designed to emit light by observing regulatory photometric grids that require respect for beaches. of specific light intensity for each of the points of these grids.

 In particular, these traffic lights must comply with geometric angles of visibility which determine the area of the minimum solid angle in which the apparent surface of the light must be visible (ECE Regulation 48 2.13). This zone is determined by the segments of a sphere whose center coincides with the reference center of the fire and whose equator is parallel to the ground. These segments are determined from the optical axis of the fire: the horizontal angles correspond to the longitude and the vertical angles to the latitude. Within these angles of geometric visibility, there must be no obstacle to the propagation of light from any point on the apparent surface of the fire observed from infinity. This regulation is particularly demanding concerning the horizontal angles that the position and direction indicators, namely 45 ° on the inner side and 80 ° on the outer side, must respect.

For issues of lower power consumption, increased life and style, it is now common to use as an alternative to light bulbs conventional incandescent, laser or electroluminescent light diodes (the latter being more commonly referred to by the acronym "LEDs").

 It is thus known, particularly from the French patent application FR 3,014,787, to associate a plurality of such diodes with a flat-type light guide (more commonly referred to as "flat guide") housed at the door. interior of the housing and adapted to transfer the light rays which feed its input surface to an exit front face located opposite said cover glass.

 In order to satisfy the regulatory photometric grid, such a light guide must thus be provided on its front face with optical elements able to spread horizontally and vertically the relatively directional luminous flux emitted by these diodes.

 Nevertheless, compliance with the minimum angles of geometric visibility for this type of traffic light is particularly difficult to obtain with point sources such as LEDs, especially in the horizontal plane.

 Recently, it is also known to use so-called surface light sources, that is to say sources whose effective light emission surface has dimensions much greater than the thickness of these sources.

 In particular, the last few years have seen the emergence of organic light-emitting diodes (OLEDs) which allow certain signaling functions to be realized, such as the position light function (or lanterns), by satisfying regulatory viewing angles while offering a great freedom of style to car manufacturers.

 The US patent application US 2014/0056020 A1 discloses a light device for a motor vehicle comprising a plurality of OLED-type independent surface light sources arranged in a circular manner.

Such a light device thus makes it possible to ensure certain signaling functions, for example the position light function by generating a homogeneous light distribution less dazzling as that produced by LED-based devices, but which remains fixed whatever the circumstances.

Object and summary of the invention

 The present invention aims to propose a light device based on surface sources having an evolutionary light distribution.

 It proposes for this purpose a light device for a motor vehicle comprising at least one surface light source constituted by an organic light-emitting diode;

 characterized in that said organic electroluminescent diode is of flexible type (FOLED) and in that said device further comprises electromechanical means adapted to cooperate with at least a portion of said FOLED to drive its deformation.

 The light device according to the invention makes it possible, thanks to the cooperation between the FOLED and the electromechanical means, to deform this FOLED in order to cause a modification of its light distribution.

 This device thus offers the possibility of ensuring an evolutionary light distribution depending on the circumstances such as, for example, a change in the driving context and / or the occurrence of certain predetermined events.

 According to preferred features of the light device according to the invention, taken alone or in combination:

 a first edge of said FOLED is fixed while said electromechanical means comprise a first actuator comprising a piston movably mounted to slide in a liner and whose free end projecting from said liner is coupled to a second edge of said FOLED, opposite said liner; first fixed edge;

 the piston of said first actuator extends in a direction transverse to the first and second edges of the FOLED;

a third edge of said FOLED is fixed while said electromechanical means further comprise a second actuator comprising a piston mounted to slide in a jacket and whose free end projecting from said liner is coupled to a fourth edge of said FOLED, opposite said third fixed edge;

 the piston of said second actuator extends in a direction transverse to said third and fourth edges of the FOLED;

 a first edge of said FOLED is fixed while said electromechanical means comprise a first actuator comprising a rotary shaft whose free end is rigidly connected to a second edge of said FOLED, opposite said first fixed edge;

 said rotary axis extends in a direction transverse to said first and second edges of the FOLED;

 said electromechanical means are coupled to a control module configured to activate them at least partially during a change in the driving context and / or the occurrence of certain predetermined events; and or

 - Said device further comprises at least one additional point light source such as a light emitting diode or laser.

 The invention also aims, in a second aspect, an optical signaling unit comprising at least one such light device.

Brief description of the drawings

 The description of the invention will now be continued by the detailed description of several exemplary embodiments, given below by way of illustration but without limitation, with reference to the appended drawings, in which:

 - Figure 1 is a schematic sectional view along a horizontal plane of an optical signal unit comprising a light device according to a first embodiment of the invention and on which the FOLED occupies a flat configuration;

FIG. 2 represents a view similar to FIG. 1 but on which the FOLED occupies a curved configuration; FIG. 3 is a schematic view in vertical cross section of an optical signaling unit comprising a light device according to a variant of this first embodiment;

 FIG. 4 is a front schematic view of an optical signal unit comprising a light device according to a second embodiment of the invention and on which all the FOLEDs occupy a plane configuration; and

 - Figure 5 shows a view similar to Figure 4 but on which one of the FOLED occupies a twisted curve configuration.

Detailed description of several preferred embodiments

Figures 1 and 2 show an optical signal unit 1 for a motor vehicle.

 In the following description and by convention, the terms "lower", "upper", "longitudinal" "lateral" and "transverse" will be defined with respect to the mounting position of such an optical unit on a vehicle.

 The optical signaling unit 1 comprises a housing 2 having an exit opening for the light rays which is closed in a sealed manner by a transparent cover glass 3.

 The optical unit 1 also comprises a light device 10 housed in the cavity delimited by the housing 2 and the cover glass 3.

 This light device 10 comprises a rectangular-shaped surface light source 11 constituted by an organic light-emitting diode (OLED).

 The basic structure of such an organic light-emitting diode (OLED) consists in superimposing several layers of organic materials between two electrode layers, one of which (usually the anode) is affixed to a substrate.

The organic thin films typically comprise a hole-conducting layer (HTL for "Hole Transport Layer" in English) deposited on the anode composed of indium-tin oxide (ITO), an emitting layer (EL for "Emission Layer" in English) containing a dye and an electron conducting layer (ETL for "Electron Transport Layer" in English).

 The operation of OLEDs is based on the principle of electroluminescence.

 By applying a suitable electrical voltage, electrons and holes are injected into the EL layer from the cathode and the anode. The electrons and holes drift toward each other and combine in this EL layer to form excitons whose disintegration provides the excitation energy of the dye molecule causing its electroluminescence. The color of the light emitted depends on the energy difference between the excited state and the base state and can therefore be modified using other dye molecules.

 The charge transfer materials, the emitting layer and the choice of electrodes are fundamental parameters that determine the performance and efficiency of the OLED.

 The organic light-emitting diode 11 is more precisely of flexible type (FOLED for Flexible Organic Light Emitting Diode): its organic layers resting on a flexible plastic substrate such as polyethylene terephthalate (PET), or even metal or glass .

 The FOLED 11 is advantageously arranged vertically inside the housing 2 so that its optical axis X is oriented in a substantially longitudinal direction.

 In order to maximize the luminance perceived from outside the optical block 1, the electrode located on the inner side of this FOLED 11 (ie: opposite to the cover glass 3) is reflective so that the light rays emitted towards inside the housing 2 are reflected towards the cover glass 3.

The FOLED 11 also comprises, at least at one of its edges, an electrical connection interface not shown and cooperating with complementary means provided on the housing 2 to ensure its power supply. A first vertical lateral edge 11A of this FOLED is also fixed rigidly to the casing 2 by means of a support 12.

 According to the invention, the light device 10 further comprises an electromechanical actuator 13 housed inside the housing 2 and connected to a continuous electric motor or not shown not step.

 This actuator 13 comprises a piston 14 slidably mounted in a sleeve 15 fixed rigidly to this housing 2 and extending in a direction transverse to the vertical lateral edges 11A, 11B of the FOLED 11.

 The free end of this piston 14 protruding out of the liner 15 is coupled to the vertical side edge 11B of this FOLED 11 located opposite the fixed edge 11A.

 In the retracted position of the piston 14, the latter exerts no force on the vertical lateral edge 11B so that the FOLED 11 occupies its plane configuration (FIG. 1) where it has, when it is lit, a spatially uniform luminance and angularly (ie orthotropic or lambertian).

 Thus, for an observer located at the rear of the vehicle (for example the driver of a follower vehicle), the visual perception of the brightness of the FOLED 11 will be identical regardless of the viewing angle.

 When the piston 14 is slidably driven by the electric motor, it exerts a transverse force on the vertical side edge 11B so as to force the FOLED 11 to adopt a substantially parabolic curved profile resulting in a change in its light distribution (FIG. 2) .

 A guide device (not shown) is advantageously provided to guide the OLED in its deformation in order to ensure in particular that it curves in the right direction.

In this case, the curvature of this FOLED 11 whose convexity is here turned outward causes a decrease in its apparent surface for an observer placed in the axis of the vehicle (for example the driver of an online follower vehicle right) and therefore an increase in its luminance, this increase being furthermore more pronounced at its central zone which therefore has a higher luminance than the two lateral zones.

 In addition, the convex profile of the FOLED 11 makes it possible to increase the level of luminous intensity emitted laterally and received by an observer placed at a significant angle of incidence relative to the axis of the vehicle (for example the driver of a follower vehicle in a sharp bend).

 On the other hand, the perceived luminance will be lower because the apparent surface of the FOLED 11 viewed from the side is larger.

 The displacement of the piston 14 of the actuator 13 (and thus the passage of the FOLED 11 in its curved configuration or vice versa) is managed by a not shown control module housed in the optical unit 1 or outside of it. last (this module can for example be integrated in the vehicle computer and be in a purely software form or in a form combining a hardware part with integrated circuits with a software part).

 This control module, coupled (directly or indirectly) to the electric motor, is configured to automatically trigger the translational movement of the piston 14 (and thus the passage of the FOLED 11 in its curved configuration) during a change of the driving context. (for example, a change in light or traffic conditions) and / or the occurrence of certain predetermined events (eg emergency braking, hazard detection, or activation / deactivation of central locking of doors), an animation in home mode, messages in traffic mode, etc.

 FIG. 3 represents a rear optical signaling unit housing a light device 10 'according to an alternative embodiment of the invention of the embodiment described above.

In the following and in this Figure 3, we kept the same references for the elements identical to the first embodiment and added a bonus for similar elements. The light device 10 'is similar to the device 10 previously described except:

 that the horizontal upper edge 11C of the FOLED 11 is also fixed rigidly to the casing 2 by means of a support 12 '; and

 - It further comprises a second electromechanical actuator 13 'housed inside the housing 2 and connected to a continuous electric motor or stepper not shown, this actuator 13' comprising a piston 14 'slidably mounted in a 15 'sleeve rigidly attached to this housing 2.

 The piston 14 'extends in a direction transverse to the upper 11C and lower 11D horizontal edges of the FOLED 11, its free end projecting from the liner 15' being coupled to the lower edge 11D located opposite the fixed edge 11C.

 In the retracted position of the pistons 14 and 14 ', the latter exert no effort on the side edges 11B and 11D lower so that the FOLED 11 occupies its planar configuration (Figure 3).

 When one of the pistons 14, 14 'is slidably driven, it comes to exert a transverse or vertical force on a corresponding edge 11B, 11D so as to force the FOLED 11 to adopt a curved profile causing a change in its light distribution.

 Electric motors driving the displacement of the pistons 14,

14 'of the actuators 13 and 13' are coupled to a control module configured to automatically trigger the translational movement of one of these pistons 14, 14 'or both simultaneously during a change of the driving context and / or the occurrence of certain predetermined events, in order to adopt different curved configurations in FOLED 11.

 Figures 4 and 5 show a rear optical block 100 signaling housing a light device 110 according to a second embodiment of the invention.

This light device 110 comprises a plurality of rectangular FOLEDs 111 (in this case, four) arranged vertically inside the housing 102 and arranged side by side. The upper horizontal edges 111C of these FOLEDs 111 are rigidly attached to the housing 102 via a respective support 112.

 The device 110 also comprises four actuators 113 housed inside the housing 102 and connected to unrepresented electric motors.

 Each actuator 113 comprises a rotary axis 114 extending in a direction transverse to the upper horizontal edges 111C and lower 111D of a respective FOLED 111, and whose free end is rigidly connected to the lower edge 111D located opposite the edge fixed 111C.

 The rotary axis 114 of each actuator 113 is adapted to adopt a first position in which the lower edge 111D of the corresponding FOLED 111 extends parallel to the upper edge 111C so that this FOLED 111 occupies its planar configuration (FIG. when illuminated, it presents a uniform luminance spatially and angularly.

 When this axis 114 is rotated by the electric motor to which it is connected, it forces the lower edge 111D to do the same so as to force the corresponding FOLED 111 to adopt a twisted curve profile (Figure 5).

 The electric motors are coupled to a control module configured to automatically trigger the rotation of the axis 114 of one or more actuators 113 simultaneously during a change in the driving context and / or the occurrence of certain events. predetermined, so as to adopt different configurations to the light device 110.

 Many other embodiments can of course be considered within the scope of the invention.

 The number of FOLEDs can thus vary and each of them can be associated with a different number of actuators of different types.

These may for example consist of a stack of plates or disks that can be expanded or compressed by piezoelectric or electrostrictive effect depending on the materials used. The actuators can also be based on other principles such as electromagnetism or the joule effect.

 Movement of some portions of the FOLED may also be inhibited in certain directions to generate more complex deformations of the FOLED (eg wavy shapes) providing a distinctive visual signature.

The luminance values currently associated with the FOLEDs (of the order of 2000 cd / m ² ) make the luminous device according to the invention particularly suitable for carrying out the position light (or lantern) function.

 It is also conceivable to integrate additional light sources (for example light-emitting diodes or laser diodes) into the light device according to the invention in order to ensure, in combination with the FOLED (s), other signaling functions such as, for example, the function STOP light or direction change indicator function.

 The optical unit housing the device according to the invention may also contain other devices capable of performing other lighting and / or signaling functions such as, for example, the function of the direction indicator lamp, the fire function. fog or the daylight running function (DRL for "Daytime running Light").

Claims

A light device for a motor vehicle comprising at least one surface light source constituted by an organic light-emitting diode (11; 111);  characterized in that said organic electroluminescent diode (11; 111) is of flexible type (FOLED) and in that said device further comprises electromechanical means (13, 13 '; 113) adapted to cooperate with at least one portion (11B, 11D; 111D) of said FOLED (11; 111) to cause its deformation.  2. Light device according to claim 1, characterized in that a first edge (11A) of said FOLED (11) is fixed, and in that said electromechanical means comprise a first actuator (13) comprising a piston (14) slidably mounted in a liner (15) and whose free end projecting from said liner (15) is coupled to a second edge (11B) of said FOLED (11) opposite said liner first fixed edge (11A).  3. Light device according to claim 2, characterized in that the piston (14) of said first actuator (13) extends in a transverse direction audits first and second edges (11A, 11B) of said FOLED (11).  4. Lighting device according to one of claims 2 or 3, characterized in that a third edge (11C) of said FOLED (11) is fixed, and in that said electromechanical means further comprise a second actuator (13 '). ) comprising a piston (14 ') slidably mounted in a liner (15') and whose free end projecting from said liner (15 ') is coupled to a fourth edge (11D) of said opposite FOLED (11) at said third fixed edge (11C). 5. Lighting device according to claim 4, characterized in that the piston (14 ') of said second actuator (13') extends according to a transverse direction to said third and fourth edges (11C, 11D) of said FOLED (11).  6. Light device according to claim 1, characterized in that a first edge (111C) of said FOLED (111) is fixed, and in that said electromechanical means comprise a first actuator (113) comprising a rotary axis (114). whose free end is rigidly connected to a second edge (111D) of said FOLED (111), opposite said first fixed edge (111C).  7. Light device according to claim 6, characterized in that said rotary axis (114) extends in a direction transverse to said first and second edges (111C, 111D) of said FOLED (111).  8. Lighting device according to one of claims 1 to 7, characterized in that said electromechanical means (13, 13 ', 113) are coupled to a control module configured to activate them at least partially during a change of context conduct and / or the occurrence of certain predetermined events.  9. Light device according to one of claims 1 to 8, characterized in that it further comprises at least one additional point light source such as a light emitting diode or laser.  10. Optical block signaling for a motor vehicle, characterized in that it comprises at least one light device according to one of claims 1 to 9.